Stealth Biotherapeutics Raises $20 Million for Mitochondrial Dysfunction Therapies

Stealth BioTherapeutics has raised $20 million in a private placement with Morningside Venture Investments to advance its pipeline of therapies targeting mitochondrial dysfunction.

Stealth’s lead candidate, elamipretide, targets the inner mitochondrial membrane where it associates with cardiolipin—the signature phospholipid of the inner mitochondrial membrane that plays a role in many mitochondrial processes, including respiration and energy conversion.

In December, Stealth reported that elamipretide failed to meet the primary endpoints in a late-stage study in patients with primary mitochondrial myopathy, but it showed promise in its ongoing Barth syndrome program.

Barth syndrome is characterized by cardiac abnormalities often leading to heart failure and reduced life expectancy, recurrent infections, muscle weakness, and delayed growth. It occurs almost exclusively in males and is estimated to affect one in 200,000 to 400,000 individuals worldwide, and there are currently no approved therapies.

The U.S. Food and Drug Administration granted Stealth Rare Pediatric Disease designation for elamipretide for the treatment of Barth syndrome in early March. Stealth has already received FDA Fast Track and Orphan Drug designations for elamipretide for the treatment of Barth.

The new financing will also be used to advance Stealth’s second compound, SBT-272, for which it initiated first-in-human testing in January for the treatment of neurodegenerative diseases involving mitochondrial dysfunction such as amyotrophic lateral sclerosis and multiple system atrophy.